The present invention relates to a safeguard apparatus for covering the cutter head of a joint planer for planing a workpiece such as lumber.
A conventional joint planer has a main safeguard covering a portion of the cutting edge exposed over the table of the planer. The main safeguard can be pivoted by the moving-in of a workpiece on the planer. One purpose of the main safeguard is to prevent damage to the cutting edge of the cutter- head. Another purpose of the main safeguard is to prevent planed chips from degrading operator efficiency and safety by flying at the joint planer operator.
In addition to the, main safeguard, the joint planer includes an auxiliary safeguard attached to the rear of the joint planer fence to cover the exposed portion of the cutting edge of the cutter head behind the fence. If a workpiece whose width is much smaller than either the width or the length of the table is to be planed, or a workpiece is to be planed away from a portion of the cutting edge of the cutter head that has been accidentally damaged, the fence of the planer is displaced in the direction of the width of the table. When the fence is displaced in this manner, it is desirable that the auxiliary safeguard cover the additional exposed portion of the cutting edge behind the fence to prevent this exposed portion from posing a danger.
As shown at FIGS. 6(A) and 6(B), fence 601 is supported by slideable bars 602, which are slideably supported by support portions 603 of body 604 of the joint planer. Fence 601 can be displaced in the direction of the width of table 605, thereby being changed in angle relative to the slideable bars. Auxiliary safeguard 608 is connected to the rear of the fence 601 by attached portion 606 of elastically deformable bendable member 607 extending from one end of the auxiliary safeguard 608. The attached portion 606 of the bendable member 607 is secured to the fence 601 so that the auxiliary safeguard 608 and the bendable member are integrally connected to fence 601.
One problem with this arrangement is that a nearly triangular gap 609 is made between the auxiliary safeguard and the surface 605a of the table 605 when the fence is disposed at an angle of 90 degrees to the surface of the table as shown in FIG. 6(A). Thus, with the fence at 90 degrees, the auxiliary safeguard 608 does not completely cover the cutter head, and the planing section of the planer can pose a danger even when the planer is not operating. If the joint planer is operating in this case, an extraneous object such as a screw or a tool can enter into the planer through gap 609 and damage the planer or be propelled outward by the rotation of the cutter head, even when no workpiece is being planed. Another problem occurs when a workpiece is being planed, as the planed chips are likely to be propelled toward the eyes of the planer operator, thereby lowering his efficiency, and possibly injuring him.
In addition, bendable member 607 makes the auxiliary safeguard difficult to use, since bendable member 607 tends to retain a bent shape, and it is time-consuming to put auxiliary safeguard 608 into tight contact with surface 605a of table 605 when the angle of the guide surface of the fence 601 relative to the surface of the table is changed from 90 to 135 degrees. Further, the useful life of bendable member 607 is relatively short, because its thickness is made small enough to render it easy to bend, and, if the bendable member is repeatedly bent or used at a low temperature, it is likely to develop a crack precipitating a break allowing the auxiliary safeguard 608 to fall off.